The influence of 2 surgical bandage systems on wound tissue oxygen tension

Hypothesis: Local wound heating improves tissue oxygen tension in postopera tive patients. Setting: University hospital. Patients: Forty normothermic and well-hydrated patients recovering from ele ctive open abdominal surgery. Interventions: A comparison between an experimental bandage system (Warm-Up ; Augustine Medical Inc, Eden Prairie, Minn) and conventional gauze covered with elastic adhesive (Medipore Dress-it; 3M, St Paul, Minn). The experime ntal system is heated to 38 degrees C and does not touch the wound. Main Outcome Measures: Subcutaneous tissue oxygen tension was measured post operatively and on the first postoperative day. In a subgroup, we also eval uated the effects of bandage pressure per se on tissue oxygen. Results: Initial postoperative tissue oxygen tensions were approximately 30 mm Hg greater with the experimental bandage, even before warming. Subcutan eous oxygen tension during heating remained significantly greater in patien ts with the warmed bandage than the conventional elastic bandage (116 +/- 4 0 vs 85 +/- 34 mm Hg, respectively) while the patients were breathing appro ximately 50% oxygen. The difference was smaller on the first postoperative day, but still statistically significant (82 +/- 30 vs 65 +/- 22 mm Hg, res pectively). In the subgroup analysis, tissue oxygen tension increased signi ficantly by 12 +/- 4 mm Hg when the heating bandage was substituted for a c onventional bandage (P<.001). Conclusion: In normothermic and well-hydrated surgical patients, much benef it from the heating bandage system appears to result from pressure relief T hese data suggest that relieving wound pressure markedly improves tissue pe rfusion and oxygenation.